Four College of Engineering faculty receive NSF CAREER awards

The National Science Foundation has awarded four UW-Madison College of Engineering faculty with 2008 Faculty Early Career Development Award (CAREER). The NSF CAREER awards, among the most prestigious given to faculty members who are just beginning their academic careers, are granted to creative projects that integrate research and education effectively. Faculty recipients include Assistant Professor of Electrical and Computer Engineering Hongrui Jiang(also biomedical engineering), Assistant Professor of Biomedical Engineering William Murphy(also materials science), Assistant Professor of Mechanical Engineering Krishnan Suresh and Assistant Professor of Materials Science and Engineering Izabela Szlufarska(also engineering physics).

Minimally invasive medical procedures, while beneficial for patients, create a unique challenge for surgeons: operation without sight. To see inside a patient without open surgery, doctors use a laparoscope, or a camera attached to a small tube that is inserted into the body cavity receiving the operation. However, the surgeon’s view is limited to the camera angle. The operating team must stop the procedure to move or turn the laparoscope whenever it needs to adjust the view. Assistant Professor of Electrical and Computer Engineering Hongrui Jiang will use his $400,002 award to give doctors a dragonfly’s-eye view of surgery.

Dragonflies, like other insects, have compound eyes—eyes made of thousands of tiny lenses, called ommatidia, arranged in a hemisphere. Each ommatidium captures light from one specific angle. The information from all the ommatidia combines to form an image, like pixels on a screen. The spherical shape gives dragonflies a very wide field of view and excellent motion detection. However, these eyes lack one important feature: They cannot focus. Without the muscles that tune our eyes to see objects at different depths, insects see things at low resolution, depending on the number of ommatidia and proximity to an object.

Jiang’s project combines the merits of compound eyes and camera-type eyes. Leveraging liquid microlens technology he has developed, Jiang and his research team plan to build spherical arrays of tiny lenses that use hydrogels like artificial muscles to focus.

“Each individual lens is tunable, so that we can zoom in and zoom out within a certain range to maintain the high resolution,” says Jiang

If successful, a laparoscope with one of these artificial compound eyes could cover a complete cavity while fixed in one place, making surgery even less invasive while giving surgeons better sight. “If you want to focus on a certain area, you can zoom in that part of the lens,” says Jiang. The technology also could be applied to other medical imaging, such as endoscopy, or to surveillance or military purposes.

Biomedical Engineering Assistant Professor William Murphy derives inspiration for his work as a tissue engineer from studying the complex processes through which human cells develop into tissue, limbs, organs and the like. “As these organs and limbs develop, cells on one end of the tissue have to differentiate into a different cell type than cells on the other end of the tissue,” he says.

That’s where protein concentration gradients do their work. For his NSF CAREER research, Murphy hopes to generate materials that deliver such gradients to stem cells—in this case, adult human stem cells isolated from bone marrow—in a controlled way.

During natural tissue development, stem cells often exist within high and low protein concentrations, with a gradual decrease in concentration—the gradient—between. “As the tissue grows, you’ll see these spatial gradients form and ultimately go away,” says Murphy. “So, they’ll form for some period of time, go away, and a new gradient will form. Ultimately this provides one of the mechanisms that allows for organization of tissues and organs.”

The entire process sounds relatively straightforward—but in reality, replicating it to engineer tissue is extremely complex. It’s possible, says Murphy, to generate protein gradients, and it’s possible to ask, for example, some simple questions about how one protein affects one cell type. “Part of the issue is that, in vivo, cells are exposed to so many proteins and the gradients are so widely variable in their properties, concentrations, and slope of the gradient, that it’s very difficult to identify initial conditions that we’d want to explore,” he says.

To eliminate much of that guesswork, Murphy has developed an array-based approach that enables him to study, simultaneously, the effects of hundreds or thousands of different gradients on stem cells in three-dimensional culture. As a result, he is more likely to identify a gradient that will significantly affect cell behavior. “We have a better chance of collecting data that are relevant to in vivo development, and also data that are relevant for tissue engineering applications,” he says.

Eventually, Murphy hopes to mimic protein concentration gradients in his efforts to engineer tissue. For now, he is attempting to create biomaterials in which the stem cells throughout initially are homogeneous, but are exposed to heterogeneous signaling environments. “If we can spatially control whether they’re alive, first, in different parts of the material, and then second, whether they then differentiate into a particular mature cell type, then we have a pretty powerful approach for trying to engineer tissues.”

Murphy, who maintains affiliations with the Departments of Materials Science and Engineering, Pharmacology, and Orthopedics and Rehabilitation, conducts research at the interface between biology, chemistry, materials science, and engineering. Likewise, his educational plan is interdisciplinary in nature: With funding from the UW-Madison Graduate School and Stem Cell and Regenerative Medicine Center, he has developed a graduate-level fellowship program in stem cell bioengineering, biology and public policy. “The purpose of this is to allow students who have a specialty in one of these three areas to spend dedicated time in one of the other two areas,” he says. “They have an immersion experience in that field. It broadens their perspective and hopefully creates some of the leaders of interdisciplinary research for the next generation in science and engineering.”

Hoping to create a culture and mindset of interdisciplinary research in young students, and in particular, traditionally underrepresented students, Murphy is establishing a mentorship program in which he and his graduate students will expose the undergraduates to interdisciplinary research as their first research experience. He also has modified his graduate-level course in stem cell bioengineering and now offers the course to undergraduates.

Already a prolific and engaging hands-on science presenter, Murphy plans to draw on well-established outreach mechanisms, including the UW-Madison Science Expeditions event and the WiCell summer science camps, to engage kindergarten through 12th-grade students in interdisciplinary research and in stem cell bioengineering.

From automobile parts to microelectromechanical systems, engineers use computer models to optimize components for manufacture. However, when the components become geometrically complex—for example, having parts of different thickness or shape—modern techniques fail. Over the next five years, Assistant Professor of Mechanical Engineering Krishnan Suresh will devote his $400,000 award to developing a next-generation optimization framework for synthesizing geometrically complex artifacts.

“The combination of all kinds of shapes in inherent in engineering,” says Suresh. “Just because we can’t handle it doesn’t mean we don’t want to make those components. We’re trying to address that basic limitation.”

During simulation, current shape optimization techniques rely on ad hoc processes, which dramatically reduce their robustness and reliability, says Suresh. Using mathematically sound techniques such as feature sensitivity and dual representation, he will build a mathematical framework so fundamental that it can optimize virtually any manufacturable object. Thus, this research could have a major effect on industry and society, creating more efficient, less expensive and more environmentally friendly components.

Suresh first will apply his framework to specific case studies to verify the mathematical concepts. In particular, Suresh plans to work with the student hybrid vehicle teams, such as the Formula SAE Team. Every year, the Formula SAE Team designs and builds a formula-style racing car for competition against more than 100 universities and colleges. Sponsored by SAE International, the competition challenges students not only to build a high-performance car but also to reduce emissions and further knowledge of alternative fuels. The UW-Madison team currently uses commercial tools for optimizing parts, but Suresh hopes to work with the students to identify challenges inherent in cutting-edge vehicle design and address them with the new framework, while training team members in the underlying concepts of shape optimization.

“Working with them is a win-win situation,” says Suresh. “Hopefully we will help them design better parts, and they will understand the reason behind the smart design tools.”

Assistant Professor of Materials Science and Engineering Izabela Szlufarska will apply her $400,226 to unlocking the science that could lead to sensitive and specific biosensors.

Biosensors resonate at a specific frequency. When a molecule touches a biosensor, the energy dissipated in the reaction is recorded as a change in frequency. Therefore, researchers know that when the resonance changes, a molecule is present—but they don’t know which molecule the sensor detects.

Working with carbon-coated sensor surfaces developed at UW-Madison by Chemistry Professor Robert Hamers, Szlufarska will study specific molecular systems to determine the molecular mechanisms responsible for energy dissipation at the sensor interface. Armed with that knowledge, she can then create models that relate resonance shifts to specific molecules. Her models, including such factors as ionization and temperature in the environment, will enable researchers to predict relative frequency changes caused by a specific target molecule.

“The ability to predict relative resonance shifts will enable design of structures capable of real-time biosensing,” says Szlufarska. Real-time biosensors have many applications in healthcare, since carbon-based sensors could be implanted in the body to monitor levels of a specific protein or hormone. They also could have applications in military and national defense.

In addition, Szlufarska plans to conduct public outreach regarding nanobiotechnology, especially for those who may have concerns. “The idea is to take the outreach one step further and bring it to the public that might have prior biases against certain developments in nano- and biotechnology,” she says. One moderating factor that communications researchers have identified is religious and ideological values. In collaboration with Professor of Life Sciences Communication Dietram Scheufele and Professor of Zoology Jeffrey Hardin, Szlufarska will promote dialogue about science and nanotechnology among local church members through round-table and panel discussions. From these discussions, Szlufarska hopes to construct a prototype of an outreach program that builds on understanding public needs, concerns and biases.